Note : The ISD-2590 is
getting rare... Winbond dont make them no more...

I'd like to offer
many thanks to André VE2FAB who wrote this Pic program and
drew the schematics.

This project, the
Voice Keyer or voice repeater is controlled by a
microcontroler the Pic; it records your voice in a ISD
and sends it back on the air as a message. For this
project I used the ISD-2590 microcontrolor which can record up
to 90 seconds. The ISD-2560, 2575 and 25120 (60, 75
and 120 seconds) are also available.

During a
H.F. contest it is often necessary to repeat the same
information for example
"CQ CQ CQ contest de VE2HLS". The Pic 16F84A gives you
the possibility to record 1, 2 or 3 different messages for a
total of 90 seconds. The messages lengths can be
adjusted to your needs.

Operating the Voice Keyer :

Recording mode :

Place the play/record
switch in record mode. Push the PTT of your microphone
and record message #1, release the PTT, push the PTT again and
record message #2. Same sequence for #3. After the third
message the green Led will flash, press the PTT and it will
stop. If you don't
like one of your messages, you'll have to start over and
record them again. Never forget the 90 seconds limit of
the ISD-2590.

Sending a message:

Slide the play/record switch
to play mode. Push button #1 and this message will be
aired. Same sequence for #2 and #3.

Message #1 repeat
mode :

You have the option of two delay modes for message #1
With the play/record switch in play mode;
First for around a two second delay, press button #1 and button #2
Second delay around 4 seconds, press button #1 and button #3

There is two ways to
supply power to the Voice Keyer, from a 12 volts power
supply or from your radio. Most of the older radio
will supply 8 volts but on some new equipments you can
get the 5 volts supply, if your radio has that new
option, it is possible to remove the 78L05 voltage
regulator from the circuit.

Parts list :

J1 - J2 = 1/8" mono Jack

J3 - J4 = Connector 8 pins

U1 = Pic 16F84A

U2 = ISD 2560 to 2590

U3 =
78L05

Msg # 1 #
2 # 3 = Push button

Play/record = Slide Switch

Q1 =
2N2222

R1 – R7 –
R14 – R15 – R16 - R17 - R18 - R19 = 10K

R2 =
Pot 5K

R3 = 1K

R4 = 4.7K

R5 = 470K

R6 – R21
= 1K

R8 - R9 =
300 ohms

R11 = 18K

R20 =
6.8K

C1 - C3 - C4
- C6 - C7 - C9 - C11 - C14 = 100nF

C2 = 22uF
10v

C5 =
22pF

C8 - C12 -
C13 - C16 - C17 = 1nF

C10 = 4.7 uF
10V

C15= 220 uF
10V

D1 - D4 =
1N4001

D2 =
Red Led

D3 =
Green Led

The Pcbdrawing is finished, ready for the plotter.

The drawing of the PC Board
with Tango was made by François VE2JX.

Pcboard top and bottom

Pcboard bottom view

Pcboard top view

If such a project interests you, the program in format HEX
for one of these type of Pic is available on
request : 16F84A, 16F628A or 16F648A